1. Field of the Invention
This invention is generally directed to safety devices for use with power tools and particularly to extension handles for use with gasoline or electrically operated hedge trimmers. The hedge trimmers include supplemental handle mounting assemblies which are either integrally formed or selectively and clampingly engaged with the motor housings of the trimmers and which assemblies enable the trimmers and which assemblies enable the trimmers to be selectively connected and rigidly supported by elongated handles in one of a selected number of positions thereby permitting the use of the hedge trimmers to cut either elevated or extended areas of vegetable growth. The invention permits alternative alignments between the elongated handles and the trimmer housings in order to allow the trimmers to be disposed at various fixed orientations with respect to the handle during operation.
2. History of the Art
Heretofore there have been numerous proposals for making the operation of various power tools more safe and more convenient for persons using such tools. Power tools which have been designed for use by the homeowner for lawn and garden upkeep have often proved to be extremely hazardous tools. Their use has resulted in injury and even dismemberment even when the person utilizing such tools has consciously utilized them with caution. Such power equipment as gasoline and electrically operated lawnmowers, chainsaws and hedge trimmers are inherently dangerous, and therefore, it is necessary to provide the utmost care in the design and operation of such equipment.
Unfortunately, the designers of home use tools do not always recognize the enumerable situations which may occur and which make the use of power tools extremely dangerous even in the hands of the most conscientious and experienced operators. In order to provide for increased user safety especially in the field of hedge trimmers for trimming hedge rows, plants, trees, bushes, brush and other vegetation areas, product manufacturers have begun utilizing control means which require that the operator's hand be positively placed on the operating switch in order to permit power to be applied to the cutting elements of the trimmers. In the event the operator should slip, fall or otherwise lose control of the trimmer, the automatic on/off mechanism theoretically operates to stop the trimmer and thereby prevent injury to the operator.
For some reason, the design of hedge trimmers has resulted in most conventional structures having a handle which is placed immediately to the rear of the hedge cutting elements thereby requiring that the hands of an operator be disposed immediately adjacent to the cutting elements during the use of the tools. As the cutting elements are so closely disposed to the body of the operator, accidents and injuries have occurred even though the control mechanisms are automatically designed to stop the operation of the power tool when the operator's hand is removed therefrom.
The danger of possible harm or injury from power tools is especially acute when considering that such tools as hedge trimmers have electrical cords which extend from motors which are mounted to the handle portions of the trimmers. Operators frequently find that the electrical cord has become trapped or cut by the reciprocating movement of the cutting blades of the trimmers. In order to decrease the potential for liability for the poor design of mounting a power cord so closely to the cutting elements of an outdoor power tool, some manufacturers have resorted to making the initial power connection immediately adjacent to the handle itself, i.e. the operating plug for the power tool is disposed within a foot of the handle thereby prohibiting it from being engaged by the cutting elements. However, when connecting an outdoor extension cable to the plug of the power tool, the outdoor extension cable or cord becomes a mere extension of the shortened power cord. Most accidents involving a cut electrical connector will therefore involve the extension cable which frequently becomes entwined in the brush or dangles so closely adjacent to the cutting elements of the hedge trimmer that the blades thereof can easily engage and severe the insulated housing or the conductors as the hedge trimmer is moved from side to side during use.
In addition to the foregoing, when dealing with fairly large hedge rows or large areas of vegetation, cutting tools such as hedge trimmers become extremely awkward and difficult to maneuver with one hand or one arm. Current hedge trimmer designs require that the hedge trimmers be suspended or held outwardly from the body of the user by a single hand, and therefore, it is easy for the operator to become fatigued and lose control or secure a grip on the tool. Therefore, even where safety devices are utilized, injury can be caused in the fraction of a second that it takes the hand of the operator to release a positive actuated switch which controls the operation of the cutter elements.
Most hedge trimmers are designed to be utilized in close vacinity to the operator. In this manner, the operating handle of conventional hedge trimmers restricts the amount of area which can be reached by the operator during the use of the tool. Frequently, hedge rows or other areas or plants which need trimming and can be trimmed utilizing hedge trimmers require cutting at heights which are elevated or at positions well above the operator or well to one side or the other of the operator. To reach such remote areas, operators of hedge trimmers must often place themselves in a precarious position in order to extend the power tool outwardly to effectively cut or trim such an area. The awkward manipulation of power tools only adds to the risk of possible injury from their use.
Several innovations have been proposed to make the operation of power tools and especially hedge trimmers more convenient for the operator. In U.S. Pat. No. 4,197,764 to Auernhammer, a detachable handle assembly is disclosed for supporting an electrically powered hedge trimmer at a position remote from the operator. The handle assembly is shown as being adjustably clamped to a base portion by a U-shaped mounting bolt so that the angle or pitch of the garden tool can be easily changed with respect to the handle. However, the amount of torque generated by especially large hedge trimmers makes it possible for such hedge trimmers to be rotated from their clamping engagement with the mounting assemblies thereby creating a situation where the handle is only loosely connected to the hedge trimmer or garden tool. In the event the tool should rotate free or slip from its adjusted position, the cutting blades could create an immediate hazard or danger to the operator or to a bystander. Further, such a frictioned or clamped connection could lead to the inadvertent cutting of vegetation in an area which is not desired to be cut due to the tool slipping from its proper engagement with the elongated handle. Also, the elongated handle of the Auernhammer patent is mounted to an extended portion of the shortened handle of the hedge trimmer. The handle portion of the hedge trimmer is the weakest area of the trimmer and normally is constructed of a plastic housing which is extended outwardly from a central portion surrounding the motor of the trimmer. Because of this construction, it is easy to fracture the area between the motor housing and the handle of the trimmer thereby creating a situation where the electrical connections could be exposed or the cutting elements of the power tool may pose a threat of serious injury to the operator or to a bystander.
In U.S. Pat. No. 3,838,508 to Turner, Sr., a hedge trimmer is disclosed having an elongated handle portion with control means mounted remote from the cutting elements. The elongated telescopically movable handle in Turner requires that the overall design of the conventional hedge trimmers be altered in order to permit the handle means to be connected thereto. Further, the linear orientation of the handle means disclosed in Turner does not permit the hedge trimmers or cutting elements of the hedge trimmers to be oriented at an angle or pitch with respect to the handle, and therefore, does not permit their use either at elevated or extended positions with respect to the operator. The patent discloses additional operating handles which are connectable to more conventional hedge trimmers. Such handles are shown as being generally linearly extended from the shortened handle normally extending from the motor housing of the hedge trimmers. In these instances, the handle is secured to the normal operating handle of the hedge trimmers and includes extendable portions which are also engagable with either a supplemental handle mounted to the motor housing of the hedge trimmers or underlying such motor housing. Again, the extendable handles disclosed do not permit any angular or pitched adjustment of the hedge trimmer with respect to the operator and therefore do not allow for the use of the hedge trimmers in elevated or extended positions wherein the angle between the operator and the area to be cut requires an angled displacement of the cutting blade relative to the operator. In addition, the structures disclosed do not provide a rigid attachment of a handle to the most secure portion of the hedge trimmers and thus may subject the operator to an undue or undesirable amount of vibration which can be adverse to the use of the tool.
Some other examples of lawn and garden power cutting tools are disclosed in U.S. Pat. No. 3,731,380 to Mathlesen which is directed to an extensible pole for use with chainsaws, U.S. Pat. No. 3,949,817 to Rice which discloses an extensible handle for supporting a chainsaw, and U.S. Pat. No. 2,832,136 which discloses a mechanism for operating a chain cutting mechanism from a rotary power mower.